U.S. patent application number 13/461828 was filed with the patent office on 2013-05-09 for method for manufacturing of a tubular object for insertion into a body passageway.
The applicant listed for this patent is Mats ANDERSSON, Andrea SCHMID. Invention is credited to Mats ANDERSSON, Andrea SCHMID.
Application Number | 20130116662 13/461828 |
Document ID | / |
Family ID | 44317931 |
Filed Date | 2013-05-09 |
United States Patent
Application |
20130116662 |
Kind Code |
A1 |
SCHMID; Andrea ; et
al. |
May 9, 2013 |
METHOD FOR MANUFACTURING OF A TUBULAR OBJECT FOR INSERTION INTO A
BODY PASSAGEWAY
Abstract
Disclosed are a method and an apparatus for manufacturing a
medical tubular object, such as a catheter, for insertion into a
body passageway. The method comprises the steps of extruding a tube
by pushing tube material though an extrusion nozzle and cutting the
extruded tube at a predetermined length. Further, an initial part
of the extruded tube is advanced onto a tapered mandrel arranged
adjacent the extrusion nozzle such that a flared end is formed, and
after a predetermined length of the extruded tube has been advanced
onto the tapered mandrel, the tapered mandrel is moved away from
the extrusion nozzle to prevent that the rest of the extruded tube
is expanded by the tapered mandrel.
Inventors: |
SCHMID; Andrea; (Molnlycke,
SE) ; ANDERSSON; Mats; (Hisings Backa, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCHMID; Andrea
ANDERSSON; Mats |
Molnlycke
Hisings Backa |
|
SE
SE |
|
|
Family ID: |
44317931 |
Appl. No.: |
13/461828 |
Filed: |
May 2, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61481494 |
May 2, 2011 |
|
|
|
Current U.S.
Class: |
604/544 ;
264/150; 425/297 |
Current CPC
Class: |
B29C 48/355 20190201;
A61F 5/453 20130101; A61M 25/0017 20130101; B29L 2031/7542
20130101; B29C 48/2694 20190201; B29D 23/001 20130101; B29C 48/09
20190201; B29C 57/04 20130101; B29C 48/0022 20190201; B29C 48/001
20190201; A61M 25/0009 20130101; B29C 48/13 20190201; B29C 48/32
20190201 |
Class at
Publication: |
604/544 ;
264/150; 425/297 |
International
Class: |
B29C 47/00 20060101
B29C047/00; A61M 25/00 20060101 A61M025/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 2011 |
EP |
11164474.6 |
Claims
1. A method for manufacturing a medical tubular object for
insertion into a body passageway, comprising the steps of:
extruding a tube by pushing tube material though an extrusion
nozzle; and cutting the extruded tube at a predetermined length,
characterized in the steps of: advancing an initial part of the
extruded tube onto a tapered mandrel arranged adjacent the
extrusion nozzle such that a flared end is formed; and after a
predetermined length of the extruded tube has been advanced onto
the tapered mandrel, moving the tapered mandrel away from the
extrusion nozzle to prevent that the rest of the extruded tube is
expanded by the tapered mandrel.
2. The method of claim 1, wherein the medical tube object is a
catheter.
3. The method according to claim 1, wherein the tapered mandrel is
moved in a direction of the extrusion.
4. The method according to claim 1, wherein the tapered mandrel is
moved at a speed that substantially corresponds to a speed at which
the extruded tube is produced.
5. The method according to claim 1, comprising the further step of
securing the flared end of the extruded tube at the tapered
mandrel.
6. The method according to claim 1, wherein the tube material
comprises at least one of monosaccharide, disaccharide,
oligosaccharide and polysaccharide.
7. The method according to claim 1, comprising the further step of
forming an end of the tube opposite the flared end into a rounded
tip portion, said forming preferably involving melting.
8. The method according to claim 1, further comprising forming of
an opening in the tube wall, said forming preferably comprising at
least one of punching and blank cutting.
9. A urinary catheter comprising a tube for insertion into a body
passageway manufactured according to claim 1.
10. An apparatus for manufacturing a medical tubular object, such
as a catheter, for insertion into a body passageway, comprising: an
extrusion nozzle adapted to extrude a tube; an extruder arranged to
push tube material through the extrusion nozzle; and a cutting
means for cutting the extruded tube at a predetermined length,
characterized by a tapered mandrel arranged adjacent the extrusion
nozzle such that an initial part of the extruded tube is advanced
onto the tapered mandrel whereby a flared end is formed, wherein
the tapered mandrel is moveable such that the tapered mandrel can
be moved away from the extrusion nozzle after a predetermined
length of the extruded tube has been advanced onto the mandrel, to
prevent that the rest of the extruded tube is expanded by the
tapered mandrel.
11. The apparatus of claim 10, wherein the medical tube object is a
catheter.
12. The apparatus according to claim 10, wherein the tapered
mandrel is moveable in a direction of the extrusion.
13. The apparatus according to claim 10, wherein the tapered
mandrel is moveable at a speed that substantially corresponds to a
speed at which the extruded tube is produced.
14. The apparatus according to claim 10, wherein said tapered
mandrel has a conical or frusto-conical shape.
15. The apparatus according to claim 10, further comprising a
clamping arrangement for securing the initial part of the extruded
tube to the tapered mandrel as the tapered mandrel is moved away
from the extrusion nozzle.
16. The apparatus according to claim 10, further comprising at
least one of a punching means and a rounded tip forming means
arranged in the vicinity of the extrusion nozzle.
17. The apparatus according to claim 10, wherein the extrusion
nozzle further comprises a centrally protruding pin, wherein the
extrusion nozzle is arranged to extrude the tube over said
centrally protruding pin.
Description
RELATED DOCUMENTS
[0001] This application claims the benefit of priority U.S.
provisional application Ser. No. 61/481,494, filed May 2, 2011 and
European application Ser. No. 11164474.6, filed May 2, 2011, which
are herein incorporated by reference for all purposes.
FIELD OF THE INVENTION
[0002] The present invention relates to an apparatus and a method
for manufacturing a tubular object, such as a tube or a catheter,
for insertion into a body passageway.
BACKGROUND OF THE INVENTION
[0003] Many types of medical devices having a tubular object for
insertion into a body passageway are known, such as urinary
catheters, stents, etc. These tubular objects conventionally
comprise an insertable end provided with one or more draining
openings such that fluid can enter the tube, and a non-insertable
end provided with an outlet being in fluid connection with the
draining openings via the tube. The non-insertable end of the
tubular object may advantageously be flared. A flared end can
prevent that the tubular object is pushed so far into the body
passageway that the non-insertable end of the tubular object
disappears into the body passageway. A flared end also makes it
easier for an operator to get hold of the tubular object when it
should be removed the body passageway. The flared end may also
serve as a connector for connecting the tubular object to a
receptacle.
[0004] Various techniques for producing tubular objects with a
flared end are known, some of which involves extrusion. For
example, GB 744 327 discloses an extrusion process for forming an
endless tube. The extruded tube is cut into suitable lengths, and
subsequently, a tip portion and a flared end portion are formed at
the respective ends. Formation of the flared end is made by pushing
the extruded end over a conical or frusto-conical mandrel during
simultaneous heating, and the thus formed part is thereafter
immediately cooled in order to obtain a permanent deformation.
However, this known method is relatively cumbersome and costly, and
does not lend itself for fully automated manufacturing.
[0005] However, although this process allows manufacturing of
catheter tubes with a flared end, there is a need for a more
efficient production process.
SUMMARY OF THE INVENTION
[0006] It is therefore an object of the present invention to
provide a more efficient process for manufacturing of the tubular
objects with a flared end.
[0007] This object is achieved with a method and apparatus
according to the appended claims.
[0008] According to an aspect of the invention there is provided a
method for manufacturing a medical tubular object, such as a
catheter, for insertion into a body passageway, comprising the
steps of: extruding a tube by pushing tube material though an
extrusion nozzle; and cutting the extruded tube at a predetermined
length, wherein the method comprises the further steps of:
advancing an initial part of the extruded tube onto a tapered
mandrel arranged adjacent the extrusion nozzle such that a flared,
or funnel-shaped, end is formed; and after a predetermined length
of the extruded tube has been advanced onto the tapered mandrel,
moving the tapered mandrel away from the extrusion nozzle to
prevent that the rest of the extruded tube is expanded by the
tapered mandrel.
[0009] The term "tubular object" as used herein refers to an object
at least part of which forms a tube. The term "tube" here refers to
an elongated shaft with a lumen therein. The tube may typically be
an elongate hollow cylinder, but may also be a hollow shaft of
other cross-sectional shapes.
[0010] The term "tapered mandrel" indicates a mandrel with a
cross-sectional area that increases in the direction of extrusion.
For example, the tapered mandrel may have a conical or
frusto-conical shape. However, the tapered mandrel may also take
other shapes that allow formation of a flared or funnel-shaped end
of the tube.
[0011] Even though the flared end formed by the mandrel generally
has a circular cross-section, it is to be acknowledged by the
skilled addressee that non-circular cross-sections, such as oval or
elliptical cross-sections are also feasible, and may be formed in
the same way by providing a corresponding shape of the mandrel.
Further, the flared end may similarly be formed with varying
thickness around its circumference and/or along its length.
[0012] The present invention is based on the realization that by
using a moveable tapered mandrel, an initial part of the extruded
tube can be expanded into a flared end immediately after the tube
leaves the extrusion nozzle. Then the tapered mandrel can be moved
away such that it does not interfere with extrusion of the rest of
the tube. As the formation of the flared end of the tube is
integrated in the extrusion process, a more efficient production
process can be achieved compared to prior art methods.
[0013] Further, as the flared end is formed immediately after the
extruded tube has left the extrusion nozzle, the tube material is
still pliable and a flared end can be formed without any
preparatory work, such as heating, that may otherwise be required.
However, for certain materials, for example some thermoplastic
polymers, such as polyethylene, additional heating may be used.
Such additional heating may e.g. be provided by internal heating of
the mandrel, or by external application of the heating, e.g. by
directing a hot air stream towards the mandrel. However, many other
ways of accomplishing local heating are also feasible.
[0014] The immediate advancement of the initial part of the
extruded tube onto the tapered mandrel are also highly advantageous
for many other reasons. For example, this leads to a very fast and
efficient manufacturing process, since exact positioning of the
tube on the mandrel becomes very simple, whereby no time and cost
consuming post positioning is to get the tube into position to form
the flared end. The risk for cassation is also alleviated. Further,
since the connector is formed as an integrated part of the
manufacturing of the tube, no separate glueing of connector to a
shaft is necessary, and there is also a reduced risk for breakage
between the shaft and the connector. Still further, since the
material used in the shaft and the material used in the connector,
share the same manufacturing history, the properties of these
materials are more controllable.
[0015] This integrated procedure also leads to less cumbersome and
tedious handling of the material, compared to e.g. extrusion of a
tube and subsequent forming of a flared end after extrusion. This
also leads to an energy effective production. Further, the
integrated production also leads to less harm to the material,
since there is no need for repeated subsequent heating and cooling
of the material. At the end, this also leads to an increased
quality of the end product.
[0016] A flared end can prevent that the tubular object is pushed
so far into the body passageway that the non-insertable end of the
tubular object disappears into the body passageway. A flared end
also makes it easier for an operator to get hold of the tubular
object when the tubular object should be removed from the body
passageway. The flared end may also serve as a connector for
connecting the tubular object to a receptacle.
[0017] The tapered mandrel may be moved, or displaced, in a
direction of the extrusion. This allows extrusion of a
substantially straight tube while the tapered mandrel remains
within the flared end. It also allows the tapered mandrel to be
removed from the flared end of the tubular object.
[0018] The tapered mandrel may be moved at a speed that
substantially corresponds to a speed at which the extruded tube is
produced. An advantage is that the tapered mandrel can remain
within and support the flared end throughout the extrusion
process.
[0019] The method may comprise securing the flared end of the
extruded tube at the tapered mandrel. This can be achieved by means
of a clamping arrangement arranged to press the flared end of the
tube against the mandrel. Thus, even if the speed at which the tube
is extruded is occasionally reduced, the tapered mandrel remains
within the flared end. The clamping arrangement also has the
additional purpose and advantage of assisting in forming the flared
end to the desired shape over the mandrel. Thus, the clamping
arrangement preferably serves the dual functions of both securing
the flared end to the mandrel and shaping the flared end into the
desired shape.
[0020] The tube material may comprise at least one of
monosaccharide, disaccharide, oligosaccharide and polysaccharide.
For example, the tube material may primarily comprise water, at
least one of sugar and starch and gelatin. Tube materials
comprising these ingredients may form degradable materials that may
be totally dissolved if maintained in water, and have also been
found to be particularly suitable for extrusion. However, the above
manufacturing method can also be used for polymers, such as
polyethylene, polypropylene or polyvinyl chloride, or any other
material suitable for extrusion.
[0021] The tube material may be heated before and/or during
extrusion, but may also be performed at room temperature. For
example, provision of heat may be advantageous for certain
thermoplastic polymers, such as polyethylene. However, for the many
materials where the formability of the material at room temperature
is sufficient to form a tube and a flared end, additional heat is
not required. To maintain the form, cooling or drying might be
used.
[0022] Subsequently, after the extruded tube has been cut, an end
of the tube opposite the flared end may be formed into a rounded
tip portion, said forming preferably involving melting.
[0023] Preferably, at least one, and preferably two or more, of a
punching means, a cutting means and a rounded tip forming means is
arranged in the vicinity of the extrusion nozzle. These means are
preferably moveable in a direction towards and away from the
extruded tube. Further, the extrusion nozzle further comprises a
centrally protruding pin, wherein the extrusion nozzle is arranged
to extrude the tube over said centrally protruding pin. The
centrally protruding pin may serve as an abutment or positive stop
for the cutting and/or the punching actions, and may also serve the
purpose of maintaining the shape of the extruded tube during
punching and/or cutting.
[0024] Moreover, an opening may be formed in the tube wall, said
forming preferably comprising at least one of punching and blank
cutting. The opening may serve as a drainage opening that allows
fluid to enter a lumen of the tube.
[0025] The method is particularly useful for manufacturing of
catheters, and most preferably urinary catheters.
[0026] According to another aspect of the present invention there
is provided an apparatus for manufacturing a medical tubular
object, such as a catheter, for insertion into a body passageway,
comprising: an extrusion nozzle adapted to extrude a tube; an
extruder arranged to push tube material through the extrusion
nozzle; a cutting means for cutting the extruded tube at a
predetermined length; and a tapered mandrel arranged adjacent the
extrusion nozzle such that an initial part of the extruded tube is
advanced onto the tapered mandrel whereby a flared end is formed,
wherein the tapered mandrel is moveable such that the tapered
mandrel can be moved away from the extrusion nozzle after a
predetermined length of the extruded tube has been advanced onto
the mandrel, to prevent that the rest of the extruded tube is
expanded by the tapered mandrel.
[0027] Hereby, similar advantages as discussed above in relation to
the previous aspect of the invention are achieved.
[0028] The above described method and apparatus may be used to
produce a tube that constitutes, or is part of, a medical device,
such as a catheter, stent, etc. In particular, the above described
method and apparatus is suitable in a process for producing urinary
catheters.
[0029] These and other aspects of the invention will be apparent
from and elucidated with reference to the embodiment described
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] These and other aspects of the present invention will now be
described in more detail, with reference to the appended drawings
showing embodiment(s) of the invention.
[0031] FIGS. 1a and 1b are persepctive views schematically
illustrating an apparatus according to an embodiment of the
invention, with the clamping arrangement in an open and closed
position, respectively;
[0032] FIG. 2a-d are side views schematically illustrating a
working sequence of the apparatus of FIG. 1;
[0033] FIG. 3 is a flow chart illustrating process steps for
manufacturing a urinary catheter according to an embodiment of the
invention;
[0034] FIG. 4 schematically illustrates an embodiment of urinary
catheter manufactured by the apparatus in FIG. 1;
[0035] FIGS. 5 and 6 schematically illustrate how the flared end of
the tube in FIG. 3 can be used to connect the tube to a
receptacle;
[0036] FIG. 7 schematically illustrate a tip forming apparatus
which may be used in conjunction with the apparatus of FIG. 1;
[0037] FIG. 8 schematically illustrate an alternative tip forming
apparatus which may be used in conjunction with the apparatus of
FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0038] In the following detailed description, preferred embodiments
of the present invention will be described. However, it is to be
understood that features of the different embodiments are
exchangeable between the embodiments and may be combined in
different ways, unless anything else is specifically indicated.
Even though in the following description, numerous specific details
are set forth to provide a more thorough understanding of the
present invention, it will be apparent to one skilled in the art
that the present invention may be practiced without these specific
details. In other instances, well known constructions or functions
are not described in detail, so as not to obscure the present
invention
[0039] The invention will in the following be discussed in relation
to a urinary catheter. However, it is to be noted that the same
technical teaching may also be used for producing of other types of
medical devices insertable into a body passageway, such as other
types of catheters, stents, etc.
[0040] FIGS. 1a and 1b schematically illustrate an apparatus
according to an embodiment of the invention for manufacturing a
catheter tube for insertion into a urethra. The apparatus 1
comprises an extruder 2, which will normally include a mixing screw
(not shown) leading to an extrusion nozzle 3, such as a die. The
apparatus can also include a cutting means (not shown) for cutting
the extruded tube at a predetermined length. Extruders as such are
well-known in the art, and no detailed explanation will be provided
on the mechanics thereof. An example of an extruder is described in
US2008/0193583, which is hereby incorporated by reference.
[0041] The apparatus 1 further includes a tapered mandrel 4
arranged adjacent the extrusion nozzle 3, and being movable in a
direction of the extrusion. The tapered mandrel is arranged such
that its cross-sectional area increases in the direction of
extrusion. The tapered mandrel preferably has a conical or
frusto-conical shape. The mandrel 4 is preferably arranged on a
holding structure 6, which is movable along a guide rail 7 in a
direction towards and away from the extruder 2.
[0042] The apparatus preferably includes an openable clamping
arrangement 5 that can be closed around the tapered mandrel. Here,
the clamping arrangement includes two clamping elements that are
arranged on opposite sides of the tapered mandrel. The clamping
elements are configured such that, when the clamping elements are
closed around the tapered mandrel, the portion of an extruded tube
that has been advanced onto the tapered mandrel is pressed against
the tapered mandrel such that funnel-shaped connector end is
formed. Further, a sensor (not shown) may be used to determine a
suitable positioning of the extruded tube on the mandrel before
closing of the clamping arrangement. As the extruded tube advances
onto the tapered madrel the sensor hereby activates the closing of
the clamping elements e.g. at a position where the material covers
the tapered mandrel. When the clamping elements are closed the
funnel shaped material on the tappered mandrel surrounded by the
clamping elements is moved away from the extrusion nozzel and in
the same direction as the extrusion direction, at a speed suitable
for forming a tube.
[0043] In the illustrated example, the clamping arrangement
comprises two parts which are moveable in relation to each other.
However, the clamping arrangement may instead comprise 3, 4, or
more parts, depending on the desired shape and design of the funnel
shaped end.
[0044] The surface finish of the funnel shaped end might be smooth,
or vary in roughness, depending on the design of the outside of the
connector. The degree of smoothness/roughness may be controlled by
arranging a corresponding smoothness/roughness on the inner side of
the clamping arrangement. Further, the inner side of the clamping
arrangement may be used to form embossment, corrugation and the
like on the outer surface of the funnel shaped end. For example,
the inner side of the clamping arrangement may be used to emboss or
form a trade name on the funnel shaped end of the tubular
object.
[0045] A holding means 8, such as a holding plate, may be arranged
beneath the extruded material, to maintain the extruded tube in a
relatively straight, and preferably essentially horizontal
position. The holding plate may e.g. be connected to a rearward
part of the clamping arrangement, and be arranged to be withdrawn
along with the mandrel as it is moved away from the extruder.
[0046] FIG. 1a illustrate the apparatus with the clamping
arrangement 5 in an opened position, whereas FIG. 1b illustrate the
clamping arrangement 5 in a closed position.
[0047] A process for manufacturing a catheter tube using the
apparatus of FIG. 1 will now be described with further reference to
the flow chart in FIG. 3 and the sequential drawings FIGS.
2a-d.
[0048] To produce a catheter tube, a tube material is placed in the
extruder 2, in step 201. The tube material may vary e.g. depending
on the desired characteristics of the resulting catheter tube.
However, the process has been found to be particularly suitable for
extrusion of degradable catheter tubes, i.e. catheter tubes that
can be totally dissolved if maintained in water. Degradable
catheter tubes are preferably primarily made of sugar and/or
starch, and preferably comprise at least one of monosaccharide,
disaccharide and polysaccharide. Examples of such materials are
known from the previous application with application number
EP09171080 by the same applicant, which is hereby incorporated by
reference.
[0049] In an exemplary embodiment, the degradable material for
extrusion comprises brown syrup (50 kg), black syrup (25 kg), flour
(40 kg) water (16+19 kg), liquorices (3 l), carbon black (1 liter),
sodium chloride (500 ml), ammonium chloride (7 kg), water (1 liter)
and anise oil (60 ml). The brown syrup, flour and water (16 kg) are
mixed at room temperature until homogenous. NaCl was added and the
mixture heated to 90.degree. C. until 65-67% water content. Black
syrup water (19 kg), liquorices+1 l wate, carbon black is added and
mixed, and subsequently heated to 98.degree. C. until 70-72% water
content is reached. Salmiak (aq) and anise oil is added and mixed.
Thereafter, the mixture rested for 12 h at room temperature, and is
then ready for extrusion.
[0050] The extruder 2 is then operated, in step 202, to extrude the
tube material, e.g. by initiating the turning of the screw which
advances the tube material towards the extrusion nozzle. The tube
material can be extruded at room temperature in a "cold press"
screw extruder without temperature zones. However, it may also be
possible to heat the tube material before and/or during extrusion.
Preferably, the extruder is operated at room temperature, i.e.
23-25.degree. C. However, due to the pressure and friction obtained
during extrusion, the temperature within the extrusion screw will,
even when operated at room temperature without additional heating,
often be higher. For example, during extrusion with the
above-discussed exemplary material at room temperature, wherein a
pressure of 4-10 kPa was exerted, a temperature within the
extrusion screw of up to ca 50.degree. C. was obtained.
[0051] As the tube material is pushed through the extrusion nozzle
3, in step 203, an extruded tube 6 is formed. An initial part of
the extruded tube is immediately advanced onto the tapered mandrel
4, in step 204, and expanded such that a flared, or funnel-shaped,
end 7 is formed. This is schematically illustrated in FIG. 2a.
After a predetermined length of the extruded tube has been advanced
onto the tapered mandrel such that a desired length of the tube has
been expanded, the clamping arrangement 5 is closed around the
tapered mandrel, in step 205. This is schematically illustrated in
FIG. 2b. As the clamping elements press the flared end of the tube
against the tapered mandrel, the flared end is secured at the
mandrel. Additionally, the clamping arrangement may be configured
to form the flared into a desired shape.
[0052] In step 206, the tapered mandrel 4 is pulled away from the
extrusion nozzle 3, in the direction of extrusion, and at the same
speed as the extruded tube 6 is produced. This is schematically
illustrated in sequence in FIGS. 2b-2d. Thus, the tapered mandrel
remains within and supports the flared end throughout the extrusion
process. Further, the extruded tube is preferably stretched between
the extrusion nozzle and the tapered mandrel. If a relatively soft
material is used, the extruded material may be arranged to be
expelled in a downward or vertical direction, in order to avoid
sagging and the like. Alternatively, holding means, such as a
holding plate or the like, may be arranged to follow the extruded
material during extrusion, and to maintain the extruded material in
an essentially straight, and preferably essentially horizontal,
position. The holding means is preferably arranged to be moved
together with the mandrel during extrusion.
[0053] In step 207, the extruded tube is cut at a desired
predetermined length, such that the tube can be removed for
subsequent processing.
[0054] The thus formed open ended tube is useable for many
applications, and for many types of medical tubular objects, and
may e.g. be used as a urinary catheter. However, in case of e.g.
urinary catheters, it is often preferred to have a rounded, closed
tip portion, and drainage openings formed on the side of the
catheter end. The tubular object producible in the above-discussed
way may also be formed with such a closed distal end. For instance,
an insertable end of the tubular object (i.e. the end opposite the
flared end) can be formed into a rounded tip portion, in step 208,
by e.g. melting and/or by forming at room temperature before
drying. Further, one or more drainage openings can be formed in the
tube wall, in step 209, by e.g. punching and/or blank cutting. The
punching step might be prior to step 208 i.e prior to the forming
and/or closing of the tip end. In order to accomplish punching,
laser cut etc a pin might be inserted into the tube prior to
punching, laser cutting etc, Hereby, drainage holes can easily be
formed before closing of the tube end by forming a tip.
[0055] FIG. 7 schematically illustrate a tip forming device which
may be used in conjunction with the apparatus discussed above with
reference to FIG. 1, and which may also form an integrated part of
this apparatus. Here, the nozzle 3 of the extruder 2 is provided
with a centrally protruding pin 10. The pin 10 preferably protrudes
a certain distance, such as 1-3 cm, out from the extruder nozzle 3.
Punching means 11 are arranged radially separated from the pin 10,
and being moveable towards the pin 10 for punching holes in the
tube. Alternatively, the punching means may use laser or the like
for forming the holes, whereby no movement relative to the pin 10
is necessary.
[0056] Further, there is provided cutting means 12 radially
separated from the pin, such as a mechanical cutting tool, a laser
cutting tool or the like, for cutting of the extruded tube. In case
a mechanical cutting tool is used, the cutting tool is preferably
moveable towards the pin 10. The cutting tool is preferably
moveable in a circle around the pin 10, to effect complete cutting
of the tube. Alternatively, a plurality of cutting tools may be
provided, which together effect the complete cutting along the
circumference of the extruded tube.
[0057] The cutting tools are preferably arranged between the
punching means 11 and the extruder 2. Hereby, the cutting may be
effected either before, during of after the formation of the holes
by the punching means 11.
[0058] Further, there is preferably provided tip forming means 13
for forming a rounded, closed tip. The tip forming means 13
preferably comprises two or more parts being moveable towards each
other, and with inner surfaces being shaped to correspond to the
desired shape of the closed tip portion. Thereby, clamping of the
parts together around the tube end forms the tip portion to its
desired shape. The moveable parts may be used without any
additional heat. However, preferably, the moveable parts are heated
at their forward ends, at the surfaces arranged to be in contact
with the tube end, thereby effecting a certain degree of melting of
the tube material.
[0059] The tip forming means 13 is preferably arranged at a certain
distance from the pin 10 in the axial direction. Hereby, cutting
and hole formation may be effected when the tube is still arranged
on the pin 10, and thereafter the tube may be pulled, by the
mandrel 4 and clamping arrangement 5, away from the pin 10, and to
a position where the tip forming means 13 may form the tip
portion.
[0060] When using the tip forming device shown in FIG. 7, the
mandrel 4 will initially be brought to a position adjacent to, or
abutting, the forward end of the centrally protruding pin 10. Since
the centrally protruding pin has a relatively limited extension,
adequate formation of the extruded tube over the mandrel 4 will
still be feasible.
[0061] However, it is also possible to bring the mandrel closer to
the extrusion opening. For example, this may be effected by
providing an opening bore in the mandrel 4, and allowing the
mandrel to be at least partly pushed over the centrally protruding
pin 10, as is shown schematically in FIG. 8. Hereby, the mandrel
may be arranged as close to the extruder opening as in the
initially discussed embodiments, and still allowing a pin to extend
out from the extruder nozzle for subsequent use in tip
formation.
[0062] FIG. 4 schematically illustrates an example of a urinary
catheter 10 manufactured according to the above described
manufacturing process. The illustrated urinary catheter comprises
an insertable end 11 provided with draining openings 12 to allow
fluid to enter the tube, and a non-insertable end 13 provided with
an outlet 14, being in fluid connection with the draining openings
12 via a lumen (not shown) of the tube. Further, the non-insertable
end 13 of the tube is flared. The flared end may serve as a
connector 15 for connecting the tube to a receptacle for collection
of fluid. The flared connector 15 may be connected to the
receptacle 16 by means of a tube 17 as illustrated in FIG. 5. An
alternative is to arrange the catheter inside the receptacle 16,
such that the catheter tube may be maneuvered through an opening 17
of the receptacle and pulled out until the flared end 15 forms a
mechanical seal connection with the opening 17 at a restriction 18
of the receptacle, as illustrated in FIG. 6.
[0063] The catheters may be made in various lengths and dimensions.
Typically, the length of the catheter tube for female catheters are
in the range 50-200 mm, such as with a length in the size of 150
mm, and for male catheters may preferably in a length in the range
of 180-450 mm, such as in the size of 400 mm. The indicated lengths
refer to the length of the catheter tube excluding the flared end.
Depending on the material, the tube may be subject to some degree
of shrinkage during drying and cooling. In the exemplary degradable
material discussed above, drying at 40.degree. C. for 20 h
typically decreases the diameter with 15-18%, and the length with
8-9%. The outer diameter of the tube after drying/cooling is
preferably in the range 3-15 mm, and more preferably in the range
5-10 mm, and most preferably in the range 6-7 mm, such as 6.5 mm.
The inner diameter of the tube after drying/cooling is preferably
in the range 1-10 mm, and more preferably in the range 2-6 mm, and
most preferably in the range 3-4 mm, such as 3.4 mm. The thickness
of the tube after drying/cooling is preferably in the range 0.5-4
mm, and more preferably in the range 1-3 mm, and most preferably in
the range 1.5-2 mm. The flared end preferably has an inner diameter
at its largest end in the range 5-15 mm, and more preferably in the
range 7-12 mm, and most preferably in the range 9-11 mm, such as
10.4 mm. The length of the flared end is preferably in the range
10-100 mm, and more preferably in the range 20-60 mm, and most
preferably in the range 25-50 mm, such as 35 mm.
[0064] Specific embodiments of the invention have now been
described. However, several alternatives are possible, as would be
apparent for someone skilled in the art. For example, other types
of extruders may also be used. Such and other obvious modifications
must be considered to be within the scope of the present invention,
as it is defined by the appended claims.
* * * * *